Mineral Species containing Actinium (Ac)

**Actinium (Ac) Element Properties**
Atomic Mass	227
Atomic Number	89
Name Origins	From the Greek, aktinos = "ray."
Year Discovered	1899
Discovery Credits	Discovered by A. Debierne at Paris, France.
Remarks	Soft, Silvery-white metal which glows in the dark. Reacts with water to evolve H₂. Primarily occurs as a trace amount (a few ppm) in uranium minerals where it is a decay product of U²³⁸
References	Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.
See Also	WebElements, ChemiCool

Atomic Mass

227

Atomic Number

89

Name Origins

From the Greek, aktinos = "ray."

Year Discovered

1899

Discovery Credits

Discovered by A. Debierne at Paris, France.

Remarks

Soft, Silvery-white metal which glows in the dark. Reacts with water to evolve H₂. Primarily occurs as a trace amount (a few ppm) in uranium minerals where it is a decay product of U²³⁸

References

Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.

Symbol	Isotope Mass	Isotope Nuclide Number	Isotope Number	Natural Abundance	Half-life	Half-life Units	Decay Mode	Decay Mode MeV	Decay Mode %
Ac	227.02775	227	89	Trace	21.77	years	beta- alpha	0.041 5.043	98.6% 1.4%
Ac	228.031015	228	89	Trace	6.13	hours	beta-	2.142	100.0%

There are no minerals containing Actinium (Ac)